JP4793212B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device in which internal mechanical elements are lubricated with oil.

  When a machine element is housed in a casing and the machine element is driven, the machine element is often lubricated with oil. In this case, the oil is supplied using a tube or the like, but a throttle may be provided at the tip of the tube in order to optimize the amount of lubrication. However, there is a problem that it is difficult to produce this diaphragm.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a power transmission device that has a small-diameter hole and is easy to manufacture.

A power transmission device according to one aspect of the present invention includes a casing having a lubricating oil passage that houses a mechanical element and lubricates the mechanical element, and has an open end, and constitutes at least a part of the lubricating oil passage. and the lubricating tube, fitted to the open end of the lubricating tube has a collision detection section for preventing detachment from the lubricating tube, a flexible orifice which is inserted into the hole which constitute the lubricating oil passage, projecting The portion protrudes from the outer peripheral surface of the orifice, and the outer diameter of the outer peripheral surface of the orifice is larger than the inner diameter of the hole, and the orifice is press-fitted into the hole.

  In the power transmission device configured as described above, a small-diameter hole can be formed by providing a flexible orifice at the opening end of the lubrication tube. Therefore, manufacture becomes easy.

  Preferably, the orifice is made of resin. In this case, by using resin, it is possible to add a different color for each orifice diameter at a minute cost, and it is possible to suppress erroneous assembly.

  Preferably, the orifice is provided with a small diameter hole smaller than the inner diameter of the lubrication tube.

  Preferably, the outer peripheral surface of the lubrication tube is provided with a protrusion that contacts the casing and prevents the lubrication tube from entering the hole too deeply.

  The present invention can provide a power transmission device having a small-diameter hole that is easy to manufacture.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In addition, the embodiments can be combined.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a power transmission device according to Embodiment 1 of the present invention. Referring to FIG. 1, power transmission device 2200 has a torque converter 3200. Torque converter 3200 is a device for transmitting torque from the crankshaft of the engine to continuously variable transmission 3400. The input shaft 3210 serves as the rotating shaft of the torque converter 3200.

  Torque converter 3200 includes a fluid working chamber and a lockup mechanism 270. The fluid working chamber has three types of impellers, and the three types of impellers are a turbine runner 240, a pump impeller 230, and a stator 223.

  A disc-shaped front cover 203 is disposed on the front side of the torque converter 3200, that is, on the side close to the engine. The front cover 203 is positioned so as to extend outward from the rotation shaft, that is, to extend in the radial direction. Cover 203 serves as a front housing of torque converter 3200. A pump shell 233 is fixed to the front cover 203. The front cover 203 and the pump shell 233 form a predetermined space, and various elements of the torque converter 3200 are arranged in this space. A space surrounded by the front cover 203 and the impeller shell (pump shell) 233 is a substantially sealed space, and an automatic transmission fluid (ATF) is enclosed in this space.

  The front cover 203 is a member that receives power from the engine. When power is input from the engine to the front cover 203, the front cover 203 rotates and this rotational force is transmitted to the pump shell 233.

  The pump shell 233 constitutes the pump impeller 230, and the pump shell 233 is a component member outside the pump impeller 230. The pump impeller 230 is disposed so as to face the turbine runner 240 and can rotate around the rotation shaft of the input shaft 3210. The pump impeller 230 is provided with a blade 231 shaped to extrude ATF (working fluid) toward the turbine runner 240, and the ATF in the vicinity of the pump impeller 230 is rotated by the blade 231 as the pump impeller 230 rotates. Extruded toward the turbine runner 240 side.

  The stator 223 is interposed between the pump impeller 230 and the turbine runner 240 and functions to change the flow direction of ATF flowing from the turbine runner 240 to the pump impeller 230. The stator 223 is attached to the fixed shaft 239 via a one-way clutch 237, and can rotate only in one direction. As the one-way clutch 237, a mechanism using a roller, a sprag or a ratchet can be employed. The stator 223 is a blade for rectifying the flow of ATF returning from the turbine runner 240 to the pump impeller 230, and is made of resin or aluminum alloy.

  The turbine runner 240 has a turbine shell 243 that forms a space for circulating the ATF, and is disposed so as to face the pump impeller 230. The turbine runner 240 receives the ATF sent out by the pump impeller 230, and a rotational force is applied by the ATF. The ATF transmitted to the turbine runner 240 moves to the inner peripheral side and is sent to the pump impeller 230 again via the stator 223. The turbine runner 240 can rotate independently of the pump impeller 230.

  The pump impeller 230 rotates integrally with the front cover 203, while the turbine runner 240 rotates integrally with the lockup piston 204. A power transmission member 209 is disposed so as to come into contact with the turbine shell 243. The power transmission member 209 is integrated with the turbine shell 243 with fasteners such as rivets or bolts, and rotates together with the turbine shell 243.

  Both the power transmission member 209 and the turbine shell 243 are fixed to the turbine hub 207. The power transmission member 209 and the turbine shell 243 can rotate together with the turbine hub 207 and the input shaft 3210 as a rotation axis. The turbine hub 207 is spline-fitted to the input shaft 3210 and is located on the outer peripheral side of the input shaft 3210. The turbine hub 207 is fitted to the input shaft 3210 and functions to transmit the rotational force input to the turbine shell 243 to the input shaft 3210.

Next, the lockup mechanism 270 will be described.
The lock-up mechanism 270 is a device for directly transmitting the rotational force of the front cover 203 to the input shaft 3210, and the facing force 276 as a friction member contacts the inner peripheral surface of the front cover 203 so that the rotational force of the front cover 203 is Is transmitted to the input shaft 3210. The lockup mechanism 270 has a lockup piston 204 for attaching a facing 276. The lock-up piston 204 can move in the axial direction, that is, the direction approaching the front cover 203 and the direction moving away from the front cover 203, thereby allowing the facing 276 to abut against the front cover 203. The lock-up piston 204 is a disk-shaped member that extends in the radial direction (radial direction) of rotation, and is disposed so as to face the front cover 203.

  A facing 276 is fixed to the outer peripheral side of the lockup piston 204. A space between the front cover 203 and the lockup piston 204 is a first hydraulic chamber 210a, and a space between the lockup piston 204 and the power transmission member 209 is a second hydraulic chamber 210b.

  Each of the first and second hydraulic chambers 210a and 210b is filled with ATF, and by changing the hydraulic pressure, the lockup piston 204 is moved in a direction approaching the front cover 203 and a direction moving away from the front cover 203. It is possible.

  The operation of the lockup mechanism 270 will be described. When the torque amplifying function of the torque converter 3200 is not required, the rotational force of the front cover 203 is directly transmitted to the input shaft 3210 by bringing the facing 276 into direct contact with the front cover 203. Can do. Specifically, the ATF in the first hydraulic chamber 210a is released through the through hole 206h. As a result, the hydraulic pressure in the first hydraulic chamber 210a is lower than the hydraulic pressure in the second hydraulic chamber 210b. As a result, the lockup piston 204 moves in a direction approaching the front cover 203, and the facing 276 contacts the front cover 203. As a result, the power of the front cover 203 is transmitted to the input shaft 3210 via the facing 276, the lockup piston 204, the power transmission member 209, and the turbine hub 207. In this state, almost no power loss is generated by the torque converter 3200.

  When the torque amplifying action of the torque converter 3200 is required, ATF is fed into the first hydraulic chamber 210a through the through hole 206h. As a result, the pressure in the first hydraulic chamber 210a increases, and the lockup piston 204 is pushed back in the direction away from the front cover 203. As a result, a gap is generated between the front cover 203 and the facing 276, and the rotational force of the front cover 203 is not directly transmitted to the facing 276.

  A forward clutch 3690, a planetary gear mechanism 3300, and a continuously variable transmission 3400 are provided on the input shaft 3210 of the torque converter 3200. The continuously variable transmission 3400 can change the gear ratio steplessly. Specifically, a general automatic transmission performs a stepped transmission by a planetary gear pair, whereas the continuously variable transmission 3400 includes a pair of pulleys and a metal belt that can freely change the groove width by hydraulic pressure. Shifts. At the time of shifting, continuously variable shifting is realized by changing the pulley width. These elements are housed in a transaxle casing 3202. A transaxle housing 3201 and a transaxle rear cover 3203 are attached to both sides of the transaxle casing 3202. A torque converter 3200 is accommodated in the transaxle housing 3201. An oil pump 3100 is provided on the outer periphery of the input shaft 3210 to circulate the ATF.

  The continuously variable transmission 3400 has a primary pulley 3411 having a primary piston 3410. The primary pulley 3411 can move in the axial direction by hydraulic pressure. Thereby, the groove width (pulley width) of the primary pulley 3411 connected to the primary piston 3410 changes continuously. A metal belt 3512 is engaged with the primary pulley 3411 and the secondary pulley 3511. The metal belt 3512 is composed of, for example, a metal element and two rows of steel rings. General chains and rubber belts transmit power by a catching force, whereas metal belts transmit power by the compression action of the element (extrusion of the element).

  Secondary pulley 3511 is connected to secondary piston 3510. The position of the secondary piston 3510 can be changed by hydraulic pressure. When the secondary piston 3510 moves in the axial direction, the secondary pulley 3511 also moves in the axial direction. Thereby, the pulley width of the secondary pulley 3511 can be continuously changed.

  The gear ratio can be changed by continuously changing the width between the primary pulley 3411 and the secondary pulley 3511.

  A planetary gear mechanism 3300 constituted by a double pinion planetary gear, a reverse brake 3330, and a forward clutch 3690 are used as a mechanism for switching between forward and reverse. The reverse brake 3330 fixes the ring gear 3325 of the planetary gear mechanism 3300. Forward clutch 3690 transmits engine power to planetary gear mechanism 3300.

  The planetary gear mechanism 3300 includes a sun gear 3310 connected to the input shaft 3210, an inner peripheral side pinion gear 3324 engaged with the sun gear 3310, an outer peripheral side pinion gear 3322 engaged with the inner peripheral side pinion gear 3324, a ring gear 3325 engaged with the outer peripheral side pinion gear 3322, A shaft 3323 that rotatably holds the inner peripheral side pinion gear 3324, a shaft 3321 that rotatably holds the outer peripheral side pinion gear 3322, and a planetary carrier 3326 that holds the shafts 3323 and 3321 are provided. The sun gear 3310 is fitted on an intermediate shaft 3611 located on an extension line of the input shaft 3210. Connection and disconnection of intermediate shaft 3611 and input shaft 3210 are performed by forward clutch 3690. Forward clutch 3690 is also connected to planetary carrier 3326. When forward clutch 3690 connects input shaft 3210 and planetary carrier 3326, intermediate shaft 3611 is disconnected from input shaft 3210. On the other hand, when the forward clutch 3690 disconnects the input shaft 3210 from the planetary carrier 3326, the input shaft 3210 and the intermediate shaft 3611 are connected.

  During forward movement, forward clutch 3690 is engaged. Thereby, the input shaft 3210 and the planetary carrier 3326 are connected, and power from the engine is transmitted to the planetary carrier 3326 via the input shaft 3210 and the forward clutch 3690. Rotational force is transmitted from planetary carrier 3326 to continuously variable transmission 3400. The arrows in FIG. 1 indicate power transmission during forward movement.

  During reverse, forward clutch 3690 disconnects input shaft 3210 and planetary carrier 3326. As a result, the intermediate shaft 3611 is connected to the input shaft 3210, so that the driving force is input to the sun gear 3310. Reverse brake 3330 locks ring gear 3325. As a result, the inner peripheral side pinion gear 3324 and the outer peripheral side pinion gear 3322 rotate (revolve), and this revolution is transmitted to the continuously variable transmission 3400 via the planetary carrier 3326. The revolution direction of the planetary carrier 3326 is opposite to the rotation direction of the input shaft 3210. As a result, it is possible to transmit power with the rotation direction reversed.

  The secondary pulley 3511 is connected to the first shaft 602. A reduction drive gear 610 is provided on the outer periphery of the first shaft 602.

  A second shaft 1702 is provided in parallel with the first shaft 602. The second shaft 1702 is provided with a reduction driven gear 1703 that meshes with the reduction drive gear 610 and a differential drive pinion 1704 that rotates together with the reduction driven gear 1703. The differential gear 5000 is rotatably held by the ring gear 603 that meshes with the differential drive pinion 1704, a differential case 604 that is attached to the ring gear 603, a pinion shaft 606 that is attached to the differential case 604 using a pin 608, and the pinion shaft 606. Pinion gear 605, a pair of side gears 607 that mesh with pinion gear 605, and a rotating body 6000 that is connected to side gear 607 and transmits power.

  FIG. 2 is an enlarged cross-sectional view of the differential device in FIG. Referring to FIG. 2, differential case 604 constituting differential gear 5000 is held by bearing 700. The bearing 700 is a roller bearing, and includes an inner race 702 that contacts the differential case 604, an outer race 701 that contacts the transaxle casing 3202, and a roller 703 as a rolling element interposed between the inner race 702 and the outer race 701. And a holder 704 that holds a plurality of rollers 703. A lubrication tube 2000 is inserted into a hole 3211 provided in the transaxle casing 3202. Lubricating oil passage 3290 includes lubricating tube 2000 and orifice 2100. Orifice 2100 and lubrication tube 2000 are inserted into hole 3211. The lubrication tube 2000 is connected to an oil pump and serves as an oil transport pipe that supplies oil. In order to adjust the amount of oil discharged from the lubrication tube 2000, an orifice 2100 as a throttle valve is attached to the tip of the lubrication tube 2000. The hole 3211 is further connected to another hole 3212, and the oil supplied to the hole 3212 lubricates the bearing 700 and further lubricates the components in the rotating body 6000 and the differential gear 5000.

  An oil seal 6001 is provided in contact with the rotating body 6000 in order to prevent the oil for lubricating the differential gear 5000 from leaking to the outside. In this embodiment, an example in which the oil supplied from the lubrication tube 2000 lubricates the bearing 700 is shown. However, the present invention is not limited to this, and the oil supplied from the lubrication tube 2000 and the orifice 2100 is in the bearing 700. Alternatively, each component of the differential gear 5000 may be lubricated.

  The oil supplied from the lubrication tube 2000 may be ATF, or may be an oil dedicated to lubrication different from ATF.

  An orifice 2100 is provided to reduce the diameter of the tip of the lubrication tube 2000. This stabilizes the supply amount of oil due to the presence of the orifice 2100.

  In this embodiment, the differential gear 5000 is shown as a differential device that is not provided with a differential limiting mechanism, but the differential gear 5000 may be provided with a differential limiting mechanism.

  Moreover, in this invention, although the rotating shaft of the torque converter shown in FIG. 1 and the rotating shaft of the rotary body 6000 which transmits rotation to a wheel are shown in parallel, the power transmission device which these rotating shafts cross orthogonally is shown. The present invention may be applied to.

  Furthermore, although the torque converter is used in this embodiment, the lubrication according to the present invention is used to lubricate the components of a so-called manual transmission, in which the gear is always engaged with the clutch without using the torque converter. Tube 2000 and orifice 2100 may be used.

  FIG. 3 is a cross-sectional view of the orifice and the lubrication tube. Referring to FIG. 3, the lubrication tube 2000 includes a flexible cylindrical body 2002, a protrusion 2003 provided on the outer surface of the cylindrical body 2002, an inner peripheral surface 2005 of the cylindrical body 2002, and an end. And an opening end portion 2001 provided in the portion. The cylindrical body 2002 is made of oil-resistant rubber or the like, and oil flows into a space surrounded by the inner peripheral surface 2005 so as to contact the inner peripheral surface 2005. The protrusion 2003 serves to prevent the lubrication tube 2000 from entering the hole too much. The protrusion 2003 may be provided over the entire outer periphery of the lubrication tube 2000, or may be provided in a dot shape.

  An orifice 2100 is fitted into the open end 2001. The orifice 2100 has a large diameter hole 2102 having a relatively large diameter and a small diameter hole 2101 having a relatively small diameter. The tip of the orifice 2100 is a head portion 2104, and a small diameter hole 2101 is provided in the head portion 2104. The head portion 2104 has a cylindrical shape, and its outer diameter is D2. The inner diameter of the small diameter hole 2101 is D3. A cylindrical portion 2105 is provided so as to be connected to the head portion 2104, and a protruding portion 2103 is provided on the outer periphery of the cylindrical portion 2105. The inner peripheral surface of the cylindrical portion 2105 constitutes a large diameter hole 2102.

  Since the orifice 2100 is press-fitted into the hole 3211, the material constituting the orifice 2100 has flexibility. Specifically, it is preferably constituted by an elastic member such as rubber or resin. An end portion 3221 of the hole 3211 has a tapered shape so that the orifice 2100 can be easily inserted. The inner diameter of the hole 3211 is D1, which is slightly smaller than the outer diameter D2 of the orifice 2100. This prevents the orifice 2100 from being pressed into the hole 3211 and the orifice 2100 from coming out of the hole 3211.

  Both the hole 3211 and the orifice 2100 have a cylindrical or columnar shape, but are not limited to this, and the hole 3211 and the orifice 2100 may have a prismatic or rectangular tube shape.

  Regarding the relationship between the inner and outer diameters D1, D2, D3, and D4, it is sufficient that D1 is smaller than D2 and D3 is smaller than D4.

  The direction in which the hole 3211 extends may be orthogonal to the direction in which the hole 3212 extends, or may be an acute angle without being orthogonal.

  FIG. 4 is a cross-sectional view showing a state in which an orifice and a lubrication tube are fitted in the hole. Referring to FIG. 4, lubrication tube 2000 and orifice 2100 are engaged. Specifically, the protruding portion 2103 of the orifice 2100 is fitted to the opening end portion 2001 of the lubrication tube 2000, thereby preventing the lubrication tube 2000 from falling off the orifice 2100. Oil (ATF) is supplied in the direction indicated by the arrow 1000. The supplied oil flows through the lubrication tube 2000 and is discharged from the small diameter hole 2101 of the orifice 2100. The portion of the orifice 2100 that contacts the opening end 2001 has a tapered shape, and serves to prevent the opening end 2001 from being detached from the orifice 2100. Note that the portion of the orifice 2100 that contacts the opening end 2001 does not have to be tapered.

  In addition, the tapered surface of the end portion 3221 of the transaxle casing 3202 is close to the protruding portion 2003 of the lubrication tube 2000 and functions to prevent the lubrication tube 2000 from entering the hole 3211 too deeply.

  Although the orifice 2100 is press-fitted into the hole 3211, the lubrication tube 2000 may be press-fitted into the hole 3211 or may not be press-fitted.

  FIG. 5 is a perspective view of the orifice. Referring to FIG. 5, orifice 2100 that reduces the flow rate of oil has small diameter hole 2101, and oil is discharged from this small diameter hole 2101. The head portion 2104 may have a tapered outer peripheral surface. Further, the head portion 2104 may be cylindrical. A plurality of projecting portions 2103 are provided at intervals on the outer periphery of the cylindrical portion 2105 that is continuous with the head portion 2104. The protrusions 2103 are provided in stripes in FIG. 5, but the protrusions 2103 may be provided continuously along the circumference.

  FIG. 6 is a perspective view of an orifice according to another aspect. In FIG. 6, a thread 2113 is provided on the outer peripheral surface of the cylindrical portion 2105 of the orifice 2100. The opening end 2001 is engaged with the thread 2113, and the opening end 2001 can be prevented from coming off the orifice 2100.

  The orifice 2100 is configured separately from the lubrication tube 2000 and is fitted to the lubrication tube 2000. This fitting can be done manually by a person. The orifice 2100 is made of, for example, resin, and the outer diameter D2 of the orifice 2100 and the inner diameter D3 of the small diameter hole 2101 can be identified by changing the color of the resin. This eliminates errors in assembly of products with different orifice diameters. Regarding the fitting between the lubrication tube 2000 and the orifice 2100, the orifice 2100 may be held by the lubrication tube 2000 until the lubrication tube 2000 is inserted into the transaxle casing 2302. No particular sealing property is required for the contact portion between the orifice 2100 and the open end 2001. A step 3214 is provided to prevent the orifice 2100 from entering too deeply, and the inner diameter of the hole 3211 is made small with the step 3214 as a boundary. The power transmission device 2200 houses a bearing 700 or a differential gear 5000 as a mechanical element, has a transaxle casing 3202 having a lubricating oil passage 3290 that lubricates the mechanical element, and an open end portion 2001, and has a lubricating oil passage 3290. A lubricating tube 2000 that forms at least a part of the tube, and a protrusion 2103 that is fitted into the opening end 2001 of the lubricating tube 2000 and prevents the lubricating tube 2000 from being detached, and that constitutes the lubricating oil passage 3290. And a flexible orifice 2100 to be inserted into 3211. The outer diameter D2 of the orifice 2100 is larger than the inner diameter D1 of the hole 3211, and the orifice 2100 is press-fitted into the hole 3211.

  The orifice 2100 is provided with a small-diameter hole 2101 having a diameter smaller than the inner diameter D4 of the lubrication tube 2000. The orifice 2100 is made of resin. The lubrication tube 2000 is provided with a protrusion 2103 that prevents the lubrication tube 2000 from entering the hole 3211 too deeply.

  In the power transmission device 2200 configured as described above, the orifice 2100 can be easily manufactured and a structure with good assemblability can be provided.

(Embodiment 2)
FIG. 7 is a cross-sectional view of the lubricating oil passage in the power transmission device according to the second embodiment of the present invention. Referring to FIG. 7, in power transmission device 2200 according to the second embodiment, small diameter hole 3215 is provided at the tip of hole 3211 provided in transaxle casing 3202. The inner diameter D5 of the small diameter hole 3215 is smaller than the inner diameter D1 of the hole 3211. The small diameter hole 3215 forms an orifice, and the oil flow rate can be reduced by the small diameter hole 3215. Oil flows in the lubrication tube 2000 in the direction indicated by the arrow 1000.

  That is, the power transmission device 2200 according to the second embodiment includes a transaxle casing 3202 having a lubricating oil passage 3290 that houses a mechanical element and lubricates the mechanical element, and an open end 2001, and includes a lubricating oil passage. And a lubrication tube 2000 constituting at least a part of 3290. The transaxle casing 3202 is provided with a hole 3211 in which the lubrication tube 2000 is fitted in contact with the outer peripheral surface of the lubrication tube 2000. A small diameter hole 3215 that constitutes an orifice is provided in the transaxle casing 3202 in which oil flows in the direction indicated by the arrow 1000 in the hole 3211 and the lubrication tube 2000 and is downstream of the oil flow from the open end 2001. The inner diameter D5 of the small diameter hole 3215 is smaller than the inner diameter D1 of the hole 3211.

  The power transmission device 2200 according to the second embodiment configured as described above has the same effects as the power transmission device 2200 according to the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the power transmission device according to Embodiment 1 of this invention. It is sectional drawing which expands and shows the differential gear in FIG. It is sectional drawing of an orifice and a lubrication tube. It is sectional drawing which shows the state by which the orifice and the lubrication tube were fitted in the hole. It is a perspective view of an orifice. FIG. 6 is a perspective view of an orifice according to another aspect. It is sectional drawing of the lubricating oil path in the power transmission device according to Embodiment 2 of this invention.

Explanation of symbols

  700 Bearing, 2000 Lubrication tube, 2001 Open end, 2002 Cylindrical body, 2003 Projection, 2005 Inner peripheral surface, 2100 Orifice, 2101 Small diameter hole, 2102 Large diameter hole, 2103 Projection, 2104 Head part, 2105 Cylindrical part, 2200 Power transmission device, 2300 torque converter, 2302 transaxle casing, 3100 oil pump, 3200 torque converter, 3201 transaxle housing, 3211, 3212 hole, 3214 step, 3215 small diameter hole, 3290 lubricating oil passage.

Claims (4)

A casing having a lubricating oil passage for housing the machine element and lubricating the machine element;
A lubricating tube having an open end and constituting at least a portion of the lubricating oil passage;
Wherein is fitted to the open end of the lubricating tube has a collision detection section for preventing detachment from the lubricating tube, a flexible orifice which is inserted into a hole forming the lubricating oil passage, the protrusion The part protrudes from the outer peripheral surface of the orifice,
The power transmission device, wherein an outer diameter of an outer peripheral surface of the orifice is larger than an inner diameter of the hole, and the orifice is press-fitted into the hole.   The power transmission device according to claim 1, wherein the orifice is made of resin.   The power transmission device according to claim 1 or 2, wherein the orifice is provided with a small-diameter hole smaller than an inner diameter of the lubrication tube.   4. The power transmission according to claim 1, wherein a protruding portion that contacts the casing and prevents the lubricating tube from entering a hole too deep is provided on an outer peripheral surface of the lubricating tube. 5. apparatus.

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